Establishment of a new breeding procedure based on rice gene targeting using information of molecular genetics and attempt to generate a new variety.

为了通过基因打靶（GT）技术培育水稻新品种，本研究基于正反选择的方法，对OsRac 1基因进行了GT修饰，获得了抗稻瘟病的水稻新品种。由于OsRac 1中的G19 V取代在随机转基因水稻中显示出有效的免疫力，因此检查了原始OsRac 1基因座处的相同修饰。G19 V置换后，通过Cre-loxP介导的标记去除系统去除OsRac 1位点上残留的阳性标记。OsRac 1基因的激活被检测到分离的纯合株系的外显子1中的G到T的交替，然而，在植物中的意外的生长抑制也相关。为了获得抗砷水稻，获得了16个具有PvACR的水稻株系。

For generation of a rice new variety by gene targeting (GT) procedure, the OsRac1 was modified by GT based on positive-negative selection to generate blast fungus resistance rice. Since the G19V substitution in OsRac1 had shown the effective immunity in random transgenic rice, the same modification at the original OsRac1 locus was examined. Following to GT for G19V substitution positive-marker remained in the OsRac1 locus was removed by Cre-loxP mediated marker free system. The OsRac1 activation was detected in the gene-modified rice plants of segregated homozygous lines for the G to T alternation in the exon 1, however, unexpected growth inhibition in the plants was also associated. For generation of arsenic resistant rice, the 16 of rice plant lines having PvACR were obtained.